Structure of Novel Phosphonium-Based Ionic Liquids with S and O Substitutions from Experiments and a Mixed Quantum-Classical Approach.
Raphael Ogbodo, Gobin Raj Acharya, Ho Martin Yuen, Nicole Zmich, Furong Wang, Hideaki Shirota, Sharon I Lall-Ramnarine, James F Wishart, Andrew J Nieuwkoop, Claudio J Margulis
Author Information
Raphael Ogbodo: Department of Chemistry, The University of Iowa, Iowa City, Iowa 52242, United States. ORCID
Gobin Raj Acharya: Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States. ORCID
Ho Martin Yuen: Department of Chemistry, Queensborough Community College-CUNY, Bayside, New York 11364, United States. ORCID
Nicole Zmich: Department of Chemistry, Queensborough Community College-CUNY, Bayside, New York 11364, United States.
Furong Wang: Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States.
Hideaki Shirota: Department of Chemistry, Chiba University, Chiba 263-8522, Japan. ORCID
Sharon I Lall-Ramnarine: Department of Chemistry, Queensborough Community College-CUNY, Bayside, New York 11364, United States. ORCID
James F Wishart: Chemistry Division, Brookhaven National Laboratory, Upton, New York 11973-5000, United States. ORCID
Andrew J Nieuwkoop: Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States. ORCID
Claudio J Margulis: Department of Chemistry, The University of Iowa, Iowa City, Iowa 52242, United States. ORCID
This article presents experimental characterization information and synchrotron X-ray scattering measurements on a set of novel O- and S-substituted phosphonium-based ionic liquids (ILs) all coupled with the bis(fluorosulfonyl)imide (FSI) anion. The ILs include the ethoxyethyltriethylphosphonium (P) and triethyl[2-(ethylthio)ethyl]phosphonium (P) cations, and we contrast results on these with those for unsubstituted triethylpentylphosphonium (P). The article also introduces a physics-based protocol that combines classical force field studies on larger simulation boxes with classical and first-principles studies on smaller boxes. The method produces significantly improved () functions in the regime which in prior publications we have associated with inter- and intraionic adjacency correlations. By understanding which shorter-range structural changes improve () in the -regime of interest, we are also able to pinpoint specific deficiencies in the classical force field model. The approach we take should be quite general and could help study other complex liquids on different length scales.
